POWER RESET FIX for: Scanner powers on, loads, has display appears to scan, beeps, has no signal meter, no audio, not even on weather and possibly other problems.
This has happened to my pro-668 twice now. The fix for me was. with the scanner on, good batteries in and disconnected from any USB power do the following....
1) Pull the batteries and hold the power button for at least 60 seconds while pressing other buttons. I just press them all one at a time for a couple seconds.
2) Reinstall the batteries and power on, connect usb, test with the weather eye button to see if you now can hear audio and see a signal meter.
Repeat until you get audio on weather and squelch (white noise)